The EU brought in the banker’s bonus cap in an attempt to stop bankers making risky investments that had the potential to make them big bucks in the event of the risks paying off; should the investments fail the bank could go bankrupt, resulting in tax-payers picking up the tab.
That’s one very good reason for the government to tell the private sector what they choose to pay their employees; and not play fast & loose with their assets – expecting the tax-payer to bail them out when things go wrong (as in 2008).